Ultrasonic machining is a well known machining process whereby the surface of a workpiece is abraded by a grit contained in a slurry circulated between the workpiece surface and a vibrating tool adjacent thereto, vibrating at frequencies above the audible range, typically within the range of 19,500 to 20,500 cycles per second. The abrading tool face is usually provided with a three-dimensional form, while a negative compliment thereof is machined onto the workpiece surface. This process finds particular utility in its ability to work difficult materials, such as glass, ceramics, calcined or vitrified refractory materials and hard and/or brittle metals, which are not susceptible to machining by any other traditional technique, or even such nontraditional techniques such as electrical discharge machining, electro-chemical machining or the like.
The use of ultrasonic machining for production applications may also be limited by the time required to mount and or change the tool assembly and align the tool with the workpiece. Typical tool changing times run from 30 minutes to an hour. This is because the tool assembly itself, that is the transducer, booster, fixturing plate and tool, referred to in the art as a sonotrode, must be carefully aligned to assure very accurate alignment of the components and good tight unions, and once the assembly is properly assembled, it must be very carefully mounted and aligned on the machine tool table so it will mate accurately with the workpiece mounting and accordingly the workpiece. In many applications where the abrading time may run for very short times, say 2 to 5 minutes, the 30 minute to one hour tool change over time renders the use of ultrasonic machining as economically unjustified for such short run jobs.